Its fidelity is fleeting. Its commitment is conditional. Having pledged their troth to the Mountain West Conference on July 1, the beguiling Broncos are already engaged in divorce proceedings.

But you can’t really blame them and you might even empathize with them, for the league they joined has sprung more leaks than the Lusitania, and the league that remains is inadequate for Boise’s ambitions. Saturday’s 52-35 stomping of San Diego State improved the Broncos’ record to 9-1, and not one of their nine victims has played Boise within 10 points.

BSU’s one blemish came courtesy of TCU, which is leaving the Mountain West for the Big 12 (having jilted the Big East without actually competing in it). On the heels of BYU and Utah bolting, the Mountain West is becoming less of a destination and more of a layover. It’s where you go to await a connection.

Boise can do better. And should.

Consider: But for a missed field goal on the last play last week, the Broncos would be undefeated and in line for a lucrative BCS Bowl game. Instead, they have plunged into consideration for the comparatively modest Las Vegas and Poinsettia Bowls. Since the difference in payouts between a BCS bowl and any of those with Mountain West ties will likely exceed $16 million, the basic question facing Boise is not, “Why would you leave?” but, “Won’t you please take us with you?”

Whether the BCS survives in its current incarnation, or scales back to a single championship game to limit its antitrust liability, the Broncos stand to benefit from a better class of competition. Though Boise’s exit strategy has centered on the logistically challenging Big East Conference, that league’s revenue potential makes long distances appear less daunting.

The same would be true for San Diego State, of course, but the Aztecs are not in as much demand as are the Broncos. If SDSU seems to be playing coy while Boise is being brazen about changing conferences, this is a function of the relative strength and available alternatives of the two programs. If Boise State is the Kim Kardashian of college football, San Diego State is more like Snooki from Jersey Shore — no one’s dream date, but relatively appealing in the right light.

Sadly, the right light is not the spotlight. Though their six victories make them bowl-eligible, the Aztecs continue to come up small and unsteady against high-profile opponents. Guilty of four turnovers against both Michigan and TCU, SDSU effectively sealed its fate on this night with a pass interception and two fumbled kicks in the first 10 minutes — each of these miscues facilitating a short-field touchdown by the visitors.

It was 21-0 before SDSU’s Adam Muema nearly doubled his career yardage on an 81-yard touchdown run late in the first quarter. It was 42-14 at the half. It was over before it had a chance to get interesting.

“There is no excuse for what we did in the first half,” Aztecs linebacker Miles Burris said. “We don’t have a reason for it.”